Being particularly percise - How would you try to convince someone on
the validity of the evolutionary model?

Braggy --

This is a difficult question because it depends on the starting point
of someone's belief.  Take Pugwashjw -- you could build a DNA model to
show evolution of species and it would make no difference to them. 
There's actually very good data to show how the eye evolved, for
example:
http://www.pbs.org/wgbh/evolution/library/01/1/l_011_01.html

And DNA is such an elegant explanation of evolution that it's
surprising creationists even try to debate it.  For example, it's
being used to determine how long the AIDS virus has taken to evolve in
different primate species (see the conclusion of this technical paper,
page 6):
http://www.biochemsoctrans.org/bst/028/0275/0280275.pdf

Second, there are various aspects of evolution or Darwinian theory. 
Many creationists ask, "Why are humans not continuing to evolve from
primates?"  Evolution is a random process -- once brontosaurs are gone
there's little liklihood that they'll re-evolve.  If humans should
disappear, other species would fill the biological space.

The late Stephen Jay Gould's essays in "Natural History" are gems in
discussing evolution and dealing with creationist nonsense.  They're
published in several books, including "Dinosaur in a Haystack" and
"Bully for Brontosaurus" and "Wonderful Life."  I'd particular
recommend the first two.

Best regards,

Omnivorous-GA

To convince someone of the validity of any argument, theory, or model,
you must first understand their objections. Seek first to understand,
then to be understood. DARWIN'S PROOF by Cornelius Hunter does a very
capable job of spelling out the skeptic's position against evolution,
with enough science to make the case but no so much as to be
overwhelming. Start with a book like that and work backward.

Despite scriptor's objection, Darwinism is rooted in theological
assumptions regarding how God is allowed to behave. Darwinism as
Darwin proposed it was not atheistic but deistic. Assuming Darwinism
is atheistic is where the heated and unproductive debate comes in.

Taking the Eye is a good example, if you imagine climbing a mountain
where one side of the mountain is vertical and smooth and the other
side is a series of steps or progressions. To explain the presence of
the Eye one would have to accept oner of two routes as to how it got
there. On the one hand you could imagine that somewhere a miracle
child was born with eyeballs, optic nerves, the visual centres of the
brain etc... (This would be the evolutionary equivalent of takling the
mountain up its vertical and smooth side.) A theoretical possibility
but to all intents and purposes, impossible. An evolutionary argument
would be uch more plausible, suggesting that the eye developed as a
series of improvments and innovations.
 Evidence supporting this view comes from the similarity in the
structure of the eye across a wide range of species - indeed classes
of animals.
 One can also make an argument for the stepped view based on natural
selection. The first stages of eye evolution may have been as simple
as an ability to sense light or dark conditions. There are many ways
in which this could provide a selective advantage for thos who develop
this ability. As evolution progresses, both the clarity of image
produced and the ability of interpret images would have continued to
develop. Stereoscopic vision would arise etc. Using this as a basis it
is easy to understand why the eyesight of those animals at the top of
the food chain have a tendancy towards enhanced abilities in this
area.
This argument can be applied to all of the varying aspects of
Evolution. You must remember that Evolution is as much a study of time
as anything else. These changes would have taken thousands if not
millions of years to be developed. Thus making the gradient up the
easy side of the mountain a very shallow one indeed.

That all i can think of of the top of my head...

Hope it helps.

Before you can convince someone of the "evolutionary model", you will
need to define your terms.

"Evolution" can cary many alternate meanings.  When some hear the term
evolution, they think of the evolution or man, others think of Darwin,
etc.

Some Precision in Terms
Evolution is a scientific theory in that it proposes a concept that
explains a set of facts of phenomena.  The phenomenon in this case is
that living creatures can change over time.  Darwin proposed the
theory of evolution by natural selection.  This involves two
components:
i) Organisms change over time.
ii) Natural selection (the favoring of one organism over another due
to how well it survives in its environment) is a mechanism by which
organisms can change.

Convincing someone of evolution requires their acceptance of the first
component. How to convince someone that organisms change over time can
be difficult, especially if they are skeptical of scientific data. 
The best studies use bacteria, which change at a fast enough rate that
there change can be observed in a human lifespan.

The second component is more difficult.  This is the "meat" or most
important part of Darwinian evolution. This coponent basically says
that organisms that are better "fit" (that is able to reproduce) in
their environment will be more likely to survive.  As new individuals
with slight changes appear that make them better fit, those organisms
will survive (reproduce) better than their ancestors.  Over time these
small changes can cause an organism to "evolve" into a new organism.

This is a very technical, theoretic approach to darwinian evolution. 
You can start with this and point to scientific studies.  All other
questions of evolution hinge on these two basic components.

SciGeek

I made a comment on how the eye cannot evolve, and a few commenters
mentioned it. But where has it gone from this question??? Have I been
censored because of Bible belief.